Synthetic diamond opens windows into the deep Earth

Abstract

As a result of its singular strength and exceptional transparency, diamond plays a unique role in laboratory studies of materials under extreme pressures and temperatures. Historically, the quality and size of the diamond used have been limited to that available from nature. However, researchers can now synthesize various types of diamonds in the laboratory that are harder, tougher, and larger than those available natural diamonds. The physical properties and features of these diamonds allow scientists to study materials at pressure‐temperature conditions ranging from those at Earth's surface to those at the very center of the Earth. In essence, these synthetic diamonds offer new windows into the deep Earth.

Carbon Mineralogy and Crystal Chemistry

“…The subsequent discovery of techniques for diamond and lonsdaleite synthesis by vapor deposition at low-pressure conditions that mimic diamond formation in expanding stellar envelopes has greatly increased the potential for diamond use in science and industry (Angus et al 1968;Derjaguin and Fedoseev 1968;Angus and Hayman 1988;Spear and Dismukes 1994;Irifune and Hemley 2012). These varied efforts in diamond synthesis have produced exceptional new materials, including isotopically pure diamonds with the highest recorded thermal conductivity, semiconducting diamonds, nano-crystalline polishing powders, lonsdaleite crystals that are harder than many natural diamond, and a range of deeply colored flawless synthetic gemstones up to 10 carats (Liang et al 2009;Meng et al 2012).…”

Nano-Polycrystalline Diamond Sphere: A Gemologist's Perspective

“…How is this possible? The GRC utilizes a 6,000-tonne multi-anvil apparatus (figure 3) to achieve the required pressure of 15 gigapascals (2.18 million psi) and temperature of 2,300-2,500°C (Irifune et al, 2003;Irifune and Hemley, 2012). Interestingly, lower temperatures in the 1,600- 2,200°C range produced some areas of hexagonal synthetic diamond-or lonsdaleite, an allotrope of diamond associated with meteoritic impact, which is a naturally occurring HPHT event (Irifune et al, 2003;Sumiya and Irifune, 2005;Ohfuji and Kuroki, 2009).…”

“…In 2003, Dr. Irifune and his colleagues first reported success in producing small NPD pieces measuring approximately 1 mm (Irifune et al, 2003;Sumiya and Irifune, 2008). Today, larger sizes are being manufactured at the GRC as 1 cm (14.5 ct) brownish yellow rods suitable for shaping into forms used in a variety of applications (Irifune and Hemley, 2012).…”

Modification of Diamond Particles for Improved Dispersion in Liquid Phase

“…More over it has high transparency over a wide wavelength region and high thermal conductivity 1,2 . Therefore, many researchers have regarded diamond as one of the most promising material in various fields 3,4 . Although, diamond is composed of only sp 3 carbon atoms, but still its surface can be modified by bonding with elements other than carbon which impart new properties.Actually, the utilization of diamond needs the development of proper technologies for its surface modification to make it useful in various applications.…”